Wolbachia can reduce the capability of mosquitoes to transmit infectious diseases to humans and is currently exploited in campaigns for the control of arboviruses, like dengue and Zika. Under the assumption that Wolbachia-mediated activation of insect immunity plays a role in the reduction of mosquito vectorial capacity, we focused our attention on the Wolbachia surface protein (WSP), a potential inductor of innate immunity. We hypothesized that the heterologous expression of this protein in gut- and tissue-associated symbionts may reduce parasite transmission. We thus engineered the mosquito bacterial symbiont Asaia to express WSP (AsaiaWSP). AsaiaWSP induced activation of the host immune response in Aedes aegypti and Anopheles stephensi mosquitoes, and inhibited the development of the heartworm parasite Dirofilaria immitis in Ae. aegypti. These results consolidate previous evidence on the immune-stimulating property of WSP and make AsaiaWSP worth of further investigations as a potential tool for the control of mosquito-borne diseases.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This study was supported by Cariplo Foundation and Lombardy Region to S.E. (2017-N.1656), by Transition Grant 2015-2017-Horizon 2020 to S.E. (G42F17000140001) and by the MIUR PRIN (Italian Ministry of Education, University and Research, MIUR) to C.B., L.P. and G.F. D.D. acknowledges the baseline funding support by King Abdullah University of Science and Technology (KAUST); S.E., C.B. and M.B. thank “Fondo per il finanziamento dei Dipartimenti universitari di eccellenza” (MIUR) of the Dept. of Biosciences (University of Milan) and of the Dept. of Biology and Biotechnology “L. Spallanzani” (University of Pavia). The authors thank Prof. L. Sacchi, Prof. F. Forlani and Prof. C. Bazzocchi for their suggestions and the UNITECH platform for the microscope image acquisition.